1. Field of the Invention
The present invention relates to a backup system for a multi-source audio apparatus capable of selectively reproducing, according to a user's instruction, sound from audio signals received from a plurality of sound sources including an analog tuner. The backup system holds operation status information of the multi-source audio apparatus in the event of a shutoff of operating power due to a blackout or the like.
2. Description of the Background Art
In a multi-source audio apparatus adapted to reproduce sound from a plurality of types of audio signal sources including an analog tuner, if supply of operating power is cut off abruptly and unintentionally due to a blackout or the like, the operation will be stopped with no chance of storing the operation status at the time of cutoff. When the operation of the multi-source audio apparatus is restarted with restoration of power supply, a predetermined sequence called cold start is followed thoroughly to boot up the apparatus in its initial state. Examples of such an operation technique are disclosed in Japanese Patent Laid-Open Publication No. 2002-152875 and Japanese Patent Gazette No. 2533967.
In the above technique, it is not possible to restart the operation of the apparatus continuously from the status at the time at which the operation was stopped the last time. Moreover, it takes time before the user can use the multi-source audio apparatus MMSA fully comfortably by again carrying out a sequence of storing user-specific necessary information. This is therefore far from a user-friendly environment.
To improve the situation described above, backup processing is effective such that, in the event of an abrupt and unintentional shutoff of operating power, backup data for enabling restoration of the operation environment of the multi-source audio apparatus at the time of the shutoff is stored in a non-volatile memory. An electrically erasable programmable read-only memory (EEPROM) is used as such an on-volatile memory. The power required for the backup processing may be stored in a capacitor during operation of the multi-source audio apparatus.
To ensure complete backup of the operation status of a multi-source audio apparatus, a large-capacity EEPROM will be necessary for storing a large amount of data. In addition, a long write time will be required to store a large amount of backup data into a large-capacity EEPROM in the event of an unintentional and abrupt shutoff of operating power, and this will consume a large backup power. Thus, a large-capacitance backup capacitor is necessitated.
A large-capacitance backup capacitor is large in size and costly, and therefore is detrimental to the realization of a compact and low cost multi-source audio apparatus MMSA.